U.S. patent number 10,151,324 [Application Number 15/011,413] was granted by the patent office on 2018-12-11 for backflow stopper with acoustic barrier.
This patent grant is currently assigned to Western Digital Technologies, Inc.. The grantee listed for this patent is HGST Netherlands B.V.. Invention is credited to Darya Amin-Shahidi, Toshiki Hirano, Jeffrey D. Wilke.
United States Patent |
10,151,324 |
Amin-Shahidi , et
al. |
December 11, 2018 |
Backflow stopper with acoustic barrier
Abstract
To provide enhanced operation of data storage devices and
systems, various systems, apparatuses, and methods are provided
herein. In a first example, a backflow assembly includes a backflow
stopper comprising a frame configured to structurally support a fin
array when coupled to a fan, the fin array comprising a plurality
of flexural deformation elements and associated fin elements
arrayed in a radial arrangement to establish a pathway for airflow,
each of the flexural deformation elements configured to move an
attached fin element responsive to airflow impacting the attached
fin element. An acoustic barrier assembly is positioned adjacently
to the backflow stopper and configured to attenuate acoustic waves
emanating from the fan.
Inventors: |
Amin-Shahidi; Darya (San Jose,
CA), Hirano; Toshiki (San Jose, CA), Wilke; Jeffrey
D. (Palmer Lake, CO) |
Applicant: |
Name |
City |
State |
Country |
Type |
HGST Netherlands B.V. |
Amsterdam |
N/A |
NL |
|
|
Assignee: |
Western Digital Technologies,
Inc. (San Jose, CA)
|
Family
ID: |
59386462 |
Appl.
No.: |
15/011,413 |
Filed: |
January 29, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170218978 A1 |
Aug 3, 2017 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D
29/522 (20130101); F04D 25/0613 (20130101); F04D
25/14 (20130101) |
Current International
Class: |
F04D
25/14 (20060101); F04D 25/06 (20060101); F04D
29/52 (20060101) |
Field of
Search: |
;415/119 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
HDD Fan Control, iMac Fan Noise Fix, iMac HDD Fan Control,
downloaded on Jun. 30, 2015, 4 pages Located at:
http://www.hddfancontrol.com. cited by applicant .
PCT Application No. PCT/US2017/015259 Notification of Transmittal
of the International Search Report and the Written Opinion of the
International Searching Authority, or the Declaration, dated Apr.
20, 2017, 12 pages. cited by applicant.
|
Primary Examiner: Edgar; Richard
Claims
What is claimed is:
1. A backflow assembly comprising: a backflow stopper comprising a
frame configured to structurally support a fin array when coupled
to a fan, the fin array comprising a plurality of flexural
deformation elements and associated fin elements arrayed in a
radial arrangement to establish a pathway for airflow, each of the
flexural deformation elements configured to move an attached fin
element responsive to airflow impacting the attached fin element;
and an acoustic barrier assembly positioned adjacently to the
backflow stopper and configured to attenuate acoustic waves
emanating from the fan.
2. The backflow assembly of claim 1 wherein: the acoustic barrier
assembly comprises a pair of acoustic barrier plates; the backflow
stopper is positioned between the pair of acoustic barrier
plates.
3. The backflow assembly of claim 2 wherein: the pair of acoustic
barrier plates comprises a first plate and a second plate; the
first plate has a first plurality of apertures formed therein; the
second plate has a second plurality of apertures formed therein;
and first and second pluralities of apertures are formed in an
offset arrangement.
4. The backflow assembly of claim 2 wherein each plate of the pair
of acoustic barrier plates is formed of a material configured to
absorb at least a portion of an acoustic wave impinging
thereon.
5. The backflow assembly of claim 1 wherein: the fin array further
comprises the one or more flexural deformation elements each
individually configurable to flex and move an attached fin element
a pre-determined amount in relation to the other flexural limiting
elements and associated fin elements responsive to airflow; and the
fin element is constructed of a material configured to absorb at
least a portion of an energy of an acoustic wave impinging
thereon.
6. A data storage assembly comprising: an enclosure configured to
house at least one data storage device; a fan assembly configured
to provide airflow within the enclosure to ventilate the at least
one data storage device, wherein a plurality of acoustic waves
emanate toward an interior of the enclosure from one or more fans
of the fan assembly during operation; and a backflow assembly
coupled to the fan assembly and comprising: a fin array comprising
a plurality of fin elements arrayed to establish a pathway for
airflow, each of the fin elements configured to move in response to
airflow impacting thereon; and a frame configured to structurally
support the fin array; wherein the backflow assembly is configured
to deflect and attenuate at least a portion of the plurality of
acoustic waves away from the at least one data storage device.
7. The data storage assembly of claim 6 wherein the backflow
assembly further comprises: a first acoustic barrier plate coupled
to a first side of the frame; and a second acoustic barrier plate
coupled to a second side of the frame opposite the first side.
8. The data storage assembly of claim 7 wherein; the first acoustic
barrier plate has a first plurality of apertures formed therein;
the second acoustic barrier plate has a second plurality of
apertures formed therein; and first and second pluralities of
apertures are formed in an offset arrangement.
9. The data storage assembly of claim 8 wherein: the first and
second pluralities of apertures are configured to allow the airflow
to pass through the backflow assembly; and a flow resistance of the
backflow assembly to the airflow passing therethrough is less than
a flow resistance of the airflow passing through the data storage
device.
10. The data storage assembly of claim 8 wherein the
non-overlapping arrangement of the first and second pluralities of
apertures prevents impingement of an acoustic wave of the plurality
of acoustic waves on the at least one data storage device from the
fan assembly directly without coming into contact with the backflow
assembly.
11. The data storage assembly of claim 7 wherein the first and
second acoustic barrier plates are constructed of a material
configured to absorb at least a portion of the plurality of
acoustic waves impinging thereon.
12. The data storage assembly of claim 6 wherein the fin elements
comprise a material configured to absorb at least a portion of an
energy of the plurality of acoustic waves.
13. The data storage assembly of claim 6 wherein each of the fin
elements comprises a contoured surface configured to deflect the at
least a portion of the plurality of acoustic waves away from the at
least one data storage device.
14. The data storage assembly of claim 13 wherein the contoured
surface comprises corrugated cardboard.
15. The data storage assembly of claim 6 wherein the plurality of
fin elements comprises; a first pair of fins configured to pivot
about a first axis; and a second pair of fins configured to pivot
about a second axis orthogonal to the first axis.
16. A data storage system comprising: an enclosure housing at least
one data storage device and having a first opening on a first side
and a second opening on a second side of the enclosure opposite the
first side; a fan assembly coupled to the enclosure and configured
to draw an airflow through the first opening toward the second
opening, the fan assembly generating a plurality of acoustic waves
toward the at least one data storage device during operation; and a
backflow stopper assembly coupled to the fan assembly and
configured to deflect and attenuate at least a portion of the
plurality of acoustic waves away from the at least one data storage
device, the backflow stopper assembly comprising a fin array
comprising a plurality of fin elements arrayed to establish a
pathway for the airflow through the backflow stopper assembly, each
of the fin elements configured to move responsive to the airflow
impacting thereon; wherein the at least one data storage device
impedes the airflow through the housing by a first flow impedance
value; wherein the backflow stopper assembly impedes the airflow
through the housing by a second flow impedance value; and wherein
the second flow impedance value is less than the first flow
impedance value.
17. The data storage system of claim 16 wherein the backflow
stopper assembly further comprises a backflow stopper and a pair of
acoustic barrier plates, wherein the backflow stopper assembly is
positioned between the pair of acoustic barrier plates.
18. The data storage system of claim 17 wherein; the pair of
acoustic barrier plates comprises a first plate and a second plate;
the first plate has a first plurality of apertures formed therein;
the second plate has a second plurality of apertures formed
therein; and first and second pluralities of apertures are formed
in an offset arrangement.
19. The data storage system of claim 18 wherein the non-overlapping
arrangement of the first and second pluralities of apertures
prevents impingement of an acoustic wave of the plurality of
acoustic waves on the at least one data storage device without
coming into contact with the backflow assembly.
20. The data storage system of claim 16 wherein; each of the fin
elements comprises a material configured to absorb at least a
portion of an energy of the plurality of acoustic waves; and each
of the fin elements comprises a contoured surface configured to
deflect the at least a portion of the plurality of acoustic waves
away from the at least one data storage device.
Description
TECHNICAL FIELD
Aspects of the disclosure are related to the field of data storage
and attenuation of acoustics in data storage enclosures.
TECHNICAL BACKGROUND
Computer and network systems such as data storage systems, server
systems, cloud storage systems, personal computers, and
workstations, typically include data storage devices for storing
and retrieving data. These data storage devices can include hard
disk drives (HDDs), solid state storage drives (SSDs), tape storage
devices, optical storage drives, hybrid storage devices that
include both rotating and solid state data storage elements, and
other mass storage devices.
As computer systems and networks grow in numbers and capability,
there is a need for ever increasing storage capacity. Data centers,
cloud computing facilities, and other at-scale data processing
systems have further increased the need for digital data storage
systems capable of transferring and holding immense amounts of
data. Data centers can house this large quantity of data storage
devices in various rack-mounted and high-density storage
configurations.
One approach to providing sufficient data storage in data centers
is the use of arrays of independent data storage devices. Many data
storage devices can be held in an electronics enclosure. An
electronics enclosure is a modular unit that can hold and operate
independent data storage devices in an array, computer processors,
routers and other electronic equipment. The data storage devices
are held and operated in close proximity within the electronics
enclosure, so that many data storage devices can be fit into a
defined volume.
While densities and workloads for the data storage devices
increase, individual data enclosures can experience increased
failure rates due to the increased densities and higher operating
temperatures. Therefore, electronics enclosures typically include
strong cooling fans or other cooling devices. If a fan fails in an
electronics enclosure having two or more fans, the failed fan
becomes the pathway of least resistance for airflow and diverts
cooling airflow away from the data storage devices. Some
electronics enclosures include assemblies with hinged louvers that
attach to the exhaust-side of the fan. When a fan fails, the
louvers close under the force gravity or an active servo mechanism
and prevent backflow through the failing fan. These louver
assemblies are typically mounted external to the data storage
assemblies or electronics enclosures to maximize usage of interior
space for electronics components. Externally mounted backflow
louvers add bulk to the enclosure and can interfere with cables,
power cords, and walls near to the enclosure. Furthermore, louvered
designs include many moving parts which can lead to reduced
reliability of electronics enclosures.
Moreover, tight packing of data storage devices within enclosures,
such as within rack-mount modular units, can lead to harsher
vibrational and thermal environments for data storage devices.
These harsh environments, such as due to fan vibrations or other
acoustic disturbances, can affect reliability and readability of
data storage devices that incorporate rotating magnetic media.
Strong cooling fans used in these systems may result in large
acoustic disturbances on top of the disturbances due to neighboring
drives seeking. Such acoustic disturbance on the data storage
devices positioned close to cooling fans in an enclosure can be
great enough to significantly degrade the performance of those
drives positioned close to the cooling fans.
Overview
To provide enhanced operation of data storage devices and systems,
various systems, apparatuses, and methods are provided herein. In a
first example, a backflow assembly includes a backflow stopper
comprising a frame configured to structurally support a fin array
when coupled to a fan, the fin array comprising a plurality of
flexural deformation elements and associated fin elements arrayed
in a radial arrangement to establish a pathway for airflow, each of
the flexural deformation elements configured to move an attached
fin element responsive to airflow impacting the attached fin
element. An acoustic barrier assembly is positioned adjacently to
the backflow stopper and configured to attenuate acoustic waves
emanating from the fan.
In another example, a data storage assembly includes an enclosure
configured to house at least one data storage device and a fan
assembly configured to provide airflow within the enclosure to
ventilate the at least one data storage device, wherein a plurality
of acoustic waves emanate toward an interior of the enclosure from
one or more fans of the fan assembly during operation. A backflow
assembly is coupled to the fan assembly and includes a fin array
comprising a plurality of fin elements arrayed to establish a
pathway for airflow and a frame configured to structurally support
the fin array. Each of the fin elements is configured to move in
response to airflow impacting thereon. The backflow assembly is
configured to deflect and attenuate at least a portion of the
plurality of acoustic waves away from the at least one data storage
device.
In another example, a data storage system includes an enclosure
housing at least one data storage device and having a first opening
on a first side and a second opening on a second side of the
enclosure opposite the first side. A fan assembly is coupled to the
enclosure and configured to draw an airflow through the first
opening toward the second opening, the fan assembly generating a
plurality of acoustic waves toward the at least one data storage
device during operation. A backflow stopper assembly is coupled to
the fan assembly and configured to deflect and attenuate at least a
portion of the plurality of acoustic waves away from the at least
one data storage device. The backflow stopper assembly also
includes a fin array comprising a plurality of fin elements arrayed
to establish a pathway for the airflow through the backflow stopper
assembly, each of the fin elements configured to move responsive to
the airflow impacting thereon. The at least one data storage device
impedes the airflow through the housing by a first flow impedance
value, and the backflow stopper assembly impedes the airflow
through the housing by a second flow impedance value. The second
flow impedance value is less than the first flow impedance
value.
BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the disclosure can be better understood with
reference to the following drawings. The components in the drawings
are not necessarily to scale, emphasis instead being placed upon
clearly illustrating the principles of the present disclosure.
Moreover, in the drawings, like reference numerals designate
corresponding parts throughout the several views. While several
embodiments are described in connection with these drawings, the
disclosure is not limited to the embodiments disclosed herein. On
the contrary, the intent is to cover all alternatives,
modifications, and equivalents.
FIG. 1 illustrates an assembled view and an exploded view of
backflow stopper assembly for preventing backflow through a cooling
fan.
FIG. 2 illustrates an assembled view and an exploded view of fan
assembly with a backflow stopper for preventing backflow through a
cooling fan.
FIG. 3 illustrates an electronics enclosure with backflow
prevention for preventing backflow through a cooling fan.
FIG. 4A illustrates airflow within an electronics enclosure when a
cooling fan fails without backflow stopper assemblies
installed.
FIG. 4B illustrates airflow within an electronics enclosure when a
cooling fan fails with backflow stopper assemblies installed.
FIG. 5 illustrates an assembled view and an exploded view of
backflow preventer assembly for preventing backflow through a
cooling fan.
FIG. 6A illustrates a backflow preventer assembly in a closed state
for blocking backflow through a cooling fan.
FIG. 6B illustrates a backflow preventer assembly in an open state
allowing airflow through a fan.
FIG. 7 illustrates a bulkhead assembly with fans and backflow
preventers for preventing backflow through the cooling fans.
FIG. 8 illustrates a backflow assembly with acoustic vibration
disturbance reduction.
FIG. 9 illustrates a schematic diagram of a data storage system
incorporating a backflow assembly with acoustic vibration
disturbance reduction.
FIG. 10 illustrates a bulkhead assembly with a plurality of the
backflow assemblies of FIG. 8 mounted thereon.
FIG. 11 illustrates a backflow assembly with acoustic vibration
disturbance reduction.
FIG. 12 illustrates a bulkhead assembly with a plurality of the
backflow assemblies of FIG. 11 mounted thereon.
DETAILED DESCRIPTION
FIG. 1 illustrates an assembled view and an exploded view of
backflow stopper assembly 100 for preventing backflow through a
cooling fan. Backflow stopper assembly 100 comprises frame 104, fin
array 106 and flex limiter elements 112. Frame 104 is configured to
structurally support fin array 106 when coupled to a fan. Fin array
106 comprises a plurality of flexural deformation elements 108 and
associated fin elements 110 arrayed in a radial arrangement to
establish a pathway for airflow. Each of flexural deformation
elements 108 is configured to move an attached fin element 110
responsive to airflow impacting attached fin element 110. Flex
limiter elements 112 couple to frame 104 and are configured to
limit flexure of fin elements 110 beyond a predetermined flexure in
relation to frame 104 to stop backflow of air through fin array
106.
Frame 104 is configured to structurally support fin array 106 when
coupled to a fan. Frame 104 comprises coupling holes 116 matching
coupling holes 116 of fin array 106 and coupling holes 116 of flex
limiter elements 112. Frame 104 structurally supports fin array 106
by coupling fin array 106 to frame 104 using mechanical fasteners
configured to engage coupling holes 116. Suitable mechanical
fasteners comprise screws, bolts, push-in rivets, snap-lock
fasteners or other fastener compatible with coupling holes 116.
Adhesives, tapes and welds can also be used to couple fin array 106
to frame 104. Alternatively, frame 104 can comprise a plate with
holes for fasteners. In this example, frame 104 couples to fin
array 106 by the compressive force of fasteners used to secure
backflow stopper assembly 100 to a fan-mount bulkhead.
The configuration of frame 104 is selected, in part, by the fan
coupled to frame 104. Suitable fan types include axial-flow,
centrifugal and cross-flow, or other type fans, including
combinations and variations thereof. Frame 104 geometry allows a
maximum amount of airflow through frame 104 while coupled to a fan
and occupies a minimal depth so that it can be installed inside of
an electronics enclosure having limited space constraints. However,
backflow stopper assembly can also be mounted on the exterior of an
electronics enclosure. The depth of frame 104 is determined by the
depth of fin array 106 when fin elements 110 are fully open. Frame
104 permits fin elements 110 to fully open without interfering with
the fan.
Frame 104 is configurable to couple fin array 106 to a fan. FIG. 1
illustrates frame 104 and fin array 106 having coupling holes 116
so that mechanical fasteners can be used to couple fin array 106 to
a fan. Suitable mechanical fasteners comprise screws, bolts,
push-in rivets, snap-lock fasteners or other fastener compatible
with coupling holes 116. Alternatively, fin array 106 can couple to
frame 104 using snap-lock features. Adhesives, tapes and welds can
also be used to couple fin array 106 to frame 104.
One or more flex limiter elements 112 couple to frame 104. FIG. 1
illustrates frame 104 and flex limiter elements 112 having coupling
holes 116 so that mechanical fasteners can be used to couple frame
104 to flex limiter elements 112. Suitable mechanical fasteners
comprise screws, bolts, push-in rivets, snap-lock fasteners or
other fastener compatible with coupling holes 116. Alternatively,
flex limiter elements 112 can couple to frame 104 using snap-lock
features. Adhesives, tapes and welds can also be used to couple
flex limiter elements 112 to frame 104.
FIG. 1 illustrates frame 104 having a void interior for airflow to
pass through. Other examples of frame 104 can have a different
configuration including interior structural members as will be
shown below. Frame 104 as illustrated in FIG. 1 is comprised of
only perimeter structure. Frame 104 is configurable to adapt to
different fin array 106 and fan configurations.
Frame 104 can be manufactured from various materials comprising
metals, alloys, polymers, ceramics, composites or some other
material having desirable properties. The method of manufacturing
frame 104 is dependent on the material used for construction. For
example, metals or alloys can be machined or punched, while
polymers can be injection molded or vacuum formed.
Fin array 106 comprises a plurality of flexural deformation
elements 108 and associated fin elements 110 arrayed in a radial
arrangement to establish a pathway for airflow, each flexural
deformation element 108 is configured to move an attached fin
element 110 responsive to airflow impacting attached fin element
110. Fin array 106 allows airflow to pass through in only one
direction. Airflow passes through fin array 106 when fin elements
110 are in an open position and airflow is blocked when fin
elements 110 are in a closed position. One or more flex limiter
elements 112 can be used to limit flexure of fin elements 110
beyond a predetermined flexure in relation to frame 104 to stop
backflow of air through the fin array.
Fin array 106 is configured to have a thin depth when fin elements
110 are in an open position permitting backflow stopper assembly
100 to be installed on the interior of an electronics enclosure
having limited space constraints. Fin array 106 can be configured
to open fin elements 110 to a pre-determined angle in relation to a
plane parallel to fin array 106 to meet limited space constraints.
For example, fin array 106 can be configured to open fin elements
110 to 40.degree., 45.degree. or 90.degree. in relation to a plane
parallel to fin array 106. Opening fin elements 110 to 90.degree.
will consume a greater depth than opening fin elements 110 only
40.degree. using the same fin array 106. Similarly, the size of fin
elements 110 impacts the depth of fin array 106. Smaller and more
numerous fin elements 110 will consume less depth than larger and
less numerous fin elements 110 while permitting the same volume of
airflow. Additionally, fin array 106 is configurable to default to
either an open or closed state depending upon the intended
application.
Fin array 106 is configurable to selectively open or close
individual fin elements 110 via flexural deformation elements 108
responsive to airflow impacting individual fin elements 110. One
way to configure fin array 106 to have selectively opening and
closing fin elements 110 is to use different materials for flexural
deformation elements 108. However, flexural deformation elements
108 can be made in several ways. Flexural deformation elements 108
can comprise a long beam. In the case of a long beam, flexural
deformation elements 108 can utilize bending or torsional
properties of the beam. FIG. 1 provides an example of flexural
deformation elements 108 comprising a long beam that deforms in a
torsional manner. Flexural deformation elements 108 can be made
from a thin section by selecting a thin sheet or by scoring
(removing thickness locally). Additionally, flexural deformation
elements can be made by narrowing a section of material to achieve
desirable flexural deformation properties. For example, provided
the thickness and material of flexural deformation elements 108 are
generally equal, a wider flexural deformation element 108 will be
less impacted than a narrower flexural deformation element 108 by
the same airflow. FIG. 1 provides an example of flexural
deformation elements 108 made by narrowing a section of material.
Finally, a combination of all the above methods can be used to make
flexural deformation elements 108.
Some considerations when selecting materials for flexural
deformation elements 108 include cost, stiffness, and environmental
factors. Flexural deformation elements 108 flex to open and close
fin elements 110, therefore the stiffness, or the modulus of
elasticity, affects how flexural deformation elements 108 react to
changes in airflow. Stiffness of flexural deformation elements 108
can be adjusted when using the same piece of material for fin
elements 110 and flexural deformation elements 108 by selectively
removing material to form flexural deformation elements 108. FIG. 1
illustrates an example of flexural deformation elements 108 cut
from the same piece of material as fin elements 110. Alternatively,
flexural deformation elements 108 can comprise different materials
than fin elements 110. In this case, both material selection and
geometry of flexural deformation elements 108 will determine the
stiffness of flexural deformation elements 108.
Environmental factors are considered when selecting material for
flexural deformation elements 108 because backflow stopper assembly
100 can be used inside of electrical enclosures and must meet
certain industry standards. In some examples, flexural deformation
elements 108 can experience temperatures ranging from 40.degree. C.
to 60.degree. C. in operation. Therefore, structural integrity of a
material at temperature and pressure might be considered to prevent
flexural deformation elements 108 from experiencing creep or
otherwise losing shape at elevated operating temperatures and
pressures. For example, flexural deformation elements 108 might
have a U.L. approved fire rating of 94 V-0 or better. Metals,
alloys, and flame retardant materials are good examples of
materials that can be used for flexural deformation elements 108.
High-density polyethylene or ITWFormex.RTM. provide two examples of
materials that can be used for flexural deformation elements 108
and meet U.L. approved fire rating of 94 V-0 or better.
Various methods of manufacturing flexural deformation elements 108
can be employed depending upon the material selected. For example,
some materials that can be used to make flexural deformation
elements 108 are easily manufactured using stamping, die cutting or
laser cutting operations. While other materials may be better
suited to injection molding, vacuum forming, scoring or some other
operations. In some examples, fin array 106 can be constructed from
flexural deformation elements 108 made of one material and fin
elements 110 from another. Dissimilar materials can be assembled
into fin array 106 by using lamination techniques, adhesives, heat
bonds or other mechanical joining processes.
Fin elements 110 close in the event of fan failure thereby
preventing backflow that would compromise the efficiency of the
cooling system. Flexural deformation elements 108 coupled to fin
elements 110 flex to open and close fin elements 110. Flexural
deformation elements 108 elements are configurable to react to
changes in airflow and open and close fin elements 110 in response.
The flexure of flexural deformation elements 108 can be configured
by material selection and geometry. Fin elements 110 bear a minimal
structural load by airflow in the open position. Fin elements 110
are structurally loaded by airflow in the closed position. Flex
limiter elements 112 provide additional support to fin elements 110
when fin elements 110 experience load. Therefore, material strength
is not a critical factor when selecting materials for fin elements
110.
Some considerations when selecting materials for fin elements 110
include cost, stiffness, and environmental factors. Environmental
factors are considered when selecting material for fin elements 110
because backflow stopper assembly 100 can be used inside of
electrical enclosures and must meet certain industry standards. For
example, fin elements 110 might have a U.L. approved fire rating of
94 V-0 or better. In some examples, fin elements 110 can experience
temperatures ranging from 40.degree. C. to 60.degree. C. in
operation. Therefore, structural integrity of a material at
temperature and pressure might be considered to prevent fin
elements 110 from experiencing creep or otherwise losing shape at
elevated operating temperatures and pressures. Metals, alloys, and
flame retardant materials are good examples of materials that can
be used for fin elements 110. High-density polyethylene or
ITWFormex.RTM. provide two examples of materials that can be used
for fin elements 110 and meet U.L. approved fire rating of 94 V-0
or better.
Various methods of manufacturing fin elements 110 can be employed
depending upon the material selected. For example, some materials
that can be used to make fin elements 110 are easily manufactured
using stamping, die cutting and laser cutting operations. While
other materials may be better suited to injection molding, vacuum
forming, scoring or some other operations. In some examples, fin
array 106 can be constructed from fin elements 110 made of one
material and flexural deformation elements 108 from another.
Dissimilar materials can be assembled into fin array 106 by using
lamination techniques, adhesives, heat bonds or other mechanical
joining processes.
One or more flex limiter elements 112 couple to frame 104 and are
configured to limit flexure of fin elements 110 beyond a
predetermined flexure in relation to frame 104 to stop backflow of
air through fin array 106. FIG. 1 illustrates frame 104 and flex
limiter elements 112 having coupling holes 116 so that mechanical
fasteners can be used to couple frame 104 to flex limiter elements
112. Suitable mechanical fasteners comprise screws, bolts, push-in
rivets, snap-lock fasteners or other fastener compatible with
coupling holes 116. Alternatively, flex limiter elements 112 can
couple to frame 104 using snap-lock features. Adhesives, tapes and
welds can also be used to couple flex limiter elements 112 to frame
104.
Flex limiter elements 112 limit flexure of fin elements 110 beyond
a predetermined flexure in relation to frame 104 to stop backflow
of air through fin array 106 by providing mechanical interference
with fin elements 110, thereby inhibiting further movement. Figure
illustrates flex limiter elements 112 as a plate with material
removed to permit airflow through flex limiter elements 112. Flex
limiter elements 112 can be a mesh in some examples. Flex limiter
elements 112 allow fin elements 110 to be constructed of lighter
and more flexible materials by providing additional support to fin
elements 110 during load. It is desirable for flex limiter elements
to be as thin as possible while still providing the necessary
support to fin elements 110 to allow backflow stopper assembly 100
to be installed into electronic enclosures having limited space
constraints. It is also desirable that flex limiter elements 112
have minimal structure to avoid negatively impacting airflow though
backflow stopper assembly 100.
Flex limiter elements 112 can be constructed from a variety of
materials. Some considerations when selecting materials for flex
limiter elements 112 include cost, stiffness, and environmental
factors. Environmental factors are considered when selecting
material for flex limiter elements 112 because backflow stopper
assembly 100 can be used inside of electrical enclosures and must
meet certain industry standards. For example, flex limiter elements
112 might have a U.L. approved fire rating of 94 V-0 or better.
Metals, alloys, polymers, ceramics, composites or other materials
having desirable properties can be used to manufacture flex limiter
elements 112.
Methods of manufacturing flex limiter elements 112 depend on the
material used for construction. For example, some materials that
can be used to make flex limiter elements 112 are easily
manufactured using stamping, die cutting and laser cutting
operations. While other materials may be better suited to injection
molding, vacuum forming, scoring or some other operations.
FIG. 2 illustrates an assembled view and an exploded view of fan
assembly with a backflow stopper 200. Fan assembly with a backflow
stopper 200 blocks airflow from passing through a fan 214 in the
event fan 214 fails. Allowing airflow to pass through fan 214 when
fan 214 has failed can compromise the efficiency of the cooling
system in an electronic enclosure because fan 214 provides a path
of lesser resistance for airflow than moving over electronic
components. Fan assembly with a backflow stopper 200 is designed to
be compact so that it can fit in the interior of an electronics
enclosure having limited space constraints. Fan assembly with a
backflow stopper 200 can be installed into existing electronics
enclosures by mounting to the bulkhead that supports the cooling
system.
Fan assembly with a backflow stopper 200 comprises fan 214 and
backflow stopper assembly 202. Fan 214 can be any type or
configuration of fan. Backflow stopper assembly 202 is configurable
to work with any fan. Typically, fan 214 will comprise an
electronic fan used for cooling electronics enclosures.
Fan 214 comprises a mechanical fan with rotating blades to create
airflow. Fan 214 can comprise an axial-flow, centrifugal or
cross-flow, or some other type of fan, including combinations or
variations. Axial-flow fans have blades that force air to move
parallel to the shaft about which the blades rotate and are
commonly used for cooling electronic equipment and typically
comprise case mount frames for mounting the fan within an
electronics enclosure. Fan 214 further comprises a motor. Some
suitable motors for use with Fan 214 include AC, DC brushed or DC
brushless motors.
Backflow stopper assembly 202 comprises frame 204, fin array 206
and flex limiter elements 212. Backflow stopper assembly 202 is an
example of backflow stopper assembly 100; however, backflow stopper
assembly 202 can have alternative configurations and operations
than backflow stopper assembly 100.
Backflow stopper assembly 202 comprises frame 204 configured to
structurally support fin array 206 and couple fin array 206 to fan
214. Fin array 206 comprises a plurality of flexural deformation
elements 208 and associated fin elements 210 arrayed in a radial
arrangement to establish a pathway for airflow, each of flexural
deformation elements 208 is configured to move an attached fin
element 210 responsive to airflow impacting the attached fin
element 210. Backflow stopper assembly 202 also comprises one or
more flex limiter elements 212 coupled to frame 204 and configured
to limit flexure of fin elements 210 beyond a predetermined flexure
in relation to frame 204 to stop backflow of air through fin array
206.
Frame 204 is configured to structurally support fin array 206 when
coupled to fan 214. Frame 204 is configurable to structurally
support fin array 206 by coupling to fin array 206. The depth of
frame 204 is determined by the depth of fin array 206. Frame 204
permits fin elements 210 to fully open without interfering with fan
214. FIG. 2 illustrates frame 204 and fin array 206 having coupling
holes 216 so that mechanical fasteners can be used to couple frame
204 to fin array 206. Mechanical fasteners that can be used
comprise screws, bolts, push-in rivets and other fasteners for use
with coupling holes 216. Adhesives or tapes can also be used to
couple frame 204 to fin array 206. Frame 204 can mechanically
couple to fin array 206 using snap-fit geometry.
Frame 204 couples fin array 206 to fan 214. FIG. 2 illustrates
frame 204 with coupling holes 216 so that mechanical fasteners can
be used to couple frame 204 to fan 214. Suitable mechanical
fasteners comprise screws, bolts, push-in rivets, snap-lock
fasteners or other fastener compatible with coupling holes 116.
Frame 204 can also couple to fin array 206 to fan 214 using
snap-lock features.
One or more flex limiter elements 212 couple to frame 204. FIG. 2
illustrates frame 204 and flex limiter elements 212 having coupling
holes 216 so that mechanical fasteners can be used to couple frame
204 to fin array 206. Suitable mechanical fasteners comprise
screws, bolts, push-in rivets, snap-lock fasteners or other
fastener compatible with coupling holes 216. Alternatively, one or
more flex limiter elements 212 can couple to frame 204 using
snap-lock features.
FIG. 2 illustrates frame 204 having a void interior for airflow to
pass through. Other examples of frame 204 can have entirely
different configurations as will be shown. For example, frame 204
can comprise interior structural members. Frame 204 as illustrated
in FIG. 2 is comprised of only perimeter structure. Frame 204 is
configurable to adapt to different fin array 206 and fan 214
configurations.
Frame 204 can be manufactured from various materials comprising
metals, alloys, polymers, ceramics, composites or some other
materials having desirable properties. The method of manufacturing
frame 204 is dependent on the material used for construction. For
example, metals or alloys can be machined or punched, while
polymers can be injection molded or vacuum formed.
Fin array 206 comprises a plurality of flexural deformation
elements 208 and associated fin elements 210 arrayed in a radial
arrangement to establish a pathway for airflow, each flexural
deformation element 208 is configured to move an attached fin
element 210 responsive to airflow impacting attached fin element
210. Fin array 206 allows airflow to pass through in only one
direction. Airflow passes through fin array 206 when fin elements
210 are in an open position and airflow is blocked when fin
elements 210 are in a closed position. One or more flex limiter
elements 212 limits flexure of fin elements 210 beyond a
predetermined flexure in relation to frame 204 to stop backflow of
air through fin array 206.
Fin array 206 is configured to have a thin depth when fin elements
210 are in an open position permitting fan assembly with a backflow
stopper 200 to be installed on the interior of an electronics
enclosure having limited space constraints. In some examples,
backflow stopper 200 has a depth of less than 20 millimeters. Fin
array 206 can be configured to open fin elements 210 to
pre-determined angles in relation to a plane parallel to fin array
206 to meet limited space constraints. For example, fin array 206
can be configured to open fin elements 210 to 40.degree.,
45.degree. or 90.degree. in relation to a plane parallel to fin
array 206. Opening fin elements 210 to 90.degree. will consume a
greater depth than opening the same fin elements 210 only
40.degree.. Similarly, the size of fin elements 210 impacts the
depth of fin array 206. Smaller and more numerous fin elements 210
consume less depth than larger and less numerous fin elements 210
while permitting the same volume of airflow. Additionally, fin
array 206 is configurable to default to either an open or closed
state depending upon the intended application. In this example, fin
array 206 defaults to an open state.
Fin array 206 is configurable to selectively open or close
individual fin elements 210 via flexural deformation elements 208
responsive to airflow impacting the individual fin elements 210.
Flexural deformation elements 208 are configured to move an
attached fin element 210 responsive to airflow impacting fin
element 210. Flexural deformation elements 208 can be configured to
move an attached fin element 210 differing amounts responsive to
the same airflow simply by changing the geometry of flexural
deformation elements 208. For example, provided the thickness and
material of the flexural deformation elements 208 are equal, a
wider flexural deformation element 208 will be less impacted than a
narrower flexural deformation element 208 by the same airflow.
Another way to configure fin array 206 to have selectively opening
and closing fin elements 210 is to use different materials for
flexural deformation elements 208.
Fin array 206 can be formed from a single piece of a flexible
material of a predetermined thickness that establishes an open
state of fin array 206 when the airflow is provided by fan 214 and
a closed state of fin array 206 when the airflow is in a direction
opposite to that provided by fan 214. Alternatively, fin array 206
can be formed from a laminated assembly of one or more flexible
materials with a first layer of the laminated assembly of a first
thickness that establishes an open state of fin array 206 when the
airflow is provided by fan 214 and a closed state of fin array 206
when the airflow is in a direction opposite to that provided by fan
214, and the second layer of the laminated assembly of a second
thickness to form fin elements 210 and provide rigidity to fin
elements 210.
Flexural deformation elements 208 can be made in several ways.
Flexural deformation elements 208 can be configured to move an
attached fin element 210 differing amounts responsive to the same
airflow simply by changing the geometry of flexural deformation
elements 208. Another way to configure fin array 206 to have
selectively opening and closing fin elements 210 is to use
different materials for flexural deformation elements 208. Flexural
deformation elements 208 can comprise a long beam. In the case of a
long beam, flexural deformation elements 208 can utilize bending or
torsional properties of the beam. Flexural deformation elements 208
can be made from a thin section by selecting a thin sheet or by
scoring (removing thickness locally). Additionally, flexural
deformation elements can be made by narrowing a section of material
to achieve desirable flexural deformation properties. For example,
provided the thickness and material of the flexural deformation
elements 208 are generally equal, a wider flexural deformation
element 208 will be less impacted than a narrower flexural
deformation element 208 by the same airflow. Finally, a combination
of all the above methods can be used to make flexural deformation
elements 208.
Some considerations when selecting materials for flexural
deformation elements 208 include cost, stiffness, and environmental
factors. Flexural deformation elements 208 flex to open and close
fin elements 210, therefore the stiffness, or the modulus of
elasticity, affects how flexural deformation elements 208 react to
changes in airflow. Stiffness of flexural deformation elements 208
can be adjusted when using the same piece of material for fin
elements 210 and flexural deformation elements 208 by selectively
removing material to form flexural deformation elements 208. FIG. 2
illustrates an example of flexural deformation elements 208 cut
from the same piece of material as fin elements 210. Alternatively,
flexural deformation elements 208 can comprise different materials
than fin elements 210. In this case, both material selection and
geometry of flexural deformation elements 208 will determine the
stiffness of flexural deformation elements 208.
Environmental factors are considered when selecting material for
flexural deformation elements 208 because fan assembly with a
backflow stopper 200 can be used inside of electronics enclosures
and must meet certain industry standards. For example, flexural
deformation elements 208 might have a U.L. approved fire rating of
94 V-0 or better. In some examples, flexural deformation elements
208 can experience temperatures ranging from 40.degree. C. to
60.degree. C. in operation. Therefore, structural integrity of a
material at temperature and pressure might be considered to prevent
flexural deformation elements 208 from experiencing creep or
otherwise losing shape at elevated operating temperatures and
pressures. Metals, alloys, and flame retardant materials are good
examples of materials that can be used for flexural deformation
elements 208. High-density polyethylene or ITWFormex.RTM. provide
two examples of materials that can be used for flexural deformation
elements 208 and meet U.L. approved fire rating of 94 V-0 or
better.
Various methods of manufacturing flexural deformation elements 208
can be employed depending upon the material selected. For example,
some materials that can be used to make flexural deformation
elements 208 are easily manufactured using stamping, die cutting
and laser cutting operations. While other materials may be better
suited to injection molding, vacuum forming, scoring of some other
operations. In some examples, fin array 206 can be constructed from
flexural deformation elements 208 made of one material and fin
elements 210 from another. Dissimilar materials can be assembled
into fin array 206 by using lamination techniques, adhesives, heat
bonds or other mechanical joining processes.
Fin elements 210 close in the event of fan 214 failures thereby
preventing backflow that would compromise the efficiency of the
cooling system. Flexural deformation elements 208 coupled to fin
elements 210 flex to open and close fin elements 210. Flexural
deformation elements 208 elements are configurable to react to
changes in airflow and open and close fin elements 210 in response.
The flexure of flexural deformation elements 208 can be configured
by material selection and geometry. Fin elements 210 bear a minimal
structural load by airflow in the open position. Fin elements 210
are structurally loaded by airflow in the closed position. Flex
limiter elements 212 provide additional support to fin elements 210
when fin elements 210 experience load in the closed position.
Therefore, material strength is not a critical factor when
selecting materials for fin elements 210.
Some considerations when selecting materials for fin elements 210
include cost, stiffness, and environmental factors. Environmental
factors are considered when selecting material for fin elements 210
because fan assembly with a backflow stopper 202 can be used inside
of electrical enclosures and must meet certain industry standards.
For example, fin elements 210 might have a U.L. approved fire
rating of 94 V-0 or better. In some examples, fin elements 210 can
experience temperatures ranging from 40.degree. C. to 60.degree. C.
in operation. Therefore, structural integrity of a material at
temperature and pressure might be considered to prevent fin
elements 210 from experiencing creep or otherwise losing shape at
elevated operating temperatures and pressures. Metals, alloys, and
flame retardant materials are good examples of materials that can
be used for fin elements 210. High-density polyethylene or
ITWFormex.RTM. provide two examples of materials that can be used
for fin elements 210 and meet U.L. approved fire rating of 94 V-0
or better.
Various methods of manufacturing fin elements 210 can be employed
depending upon the material selected. For example, some materials
that can be used to make fin elements 210 are easily manufactured
using stamping, die cutting and laser cutting operations. While
other materials may be better suited to injection molding, vacuum
forming, scoring of some other operations. In some examples, fin
array 206 can be constructed from fin elements 210 made of one
material and flexural deformation elements 208 from another.
Dissimilar materials can be assembled to make fin array 206 by
using lamination techniques, adhesives, heat bonds or other
mechanical joining processes.
One or more flex limiter elements 212 couple to frame 204 and are
configured to limit flexure of fin elements 210 beyond a
predetermined flexure in relation to frame 204 to stop backflow of
air through fin array 206. Flex limiter elements 212 limit flexure
of fin elements 210 beyond a predetermined flexure in relation to
frame 204 to stop backflow of air through fin array 206 by
providing mechanical interference with fin elements 210 thereby
inhibiting further movement. Flex limiter elements 212 allow fin
elements 210 to be constructed of lighter and more flexible
materials by providing additional support to fin elements 210
during load. It is desirable for flex limiter elements 212 to be as
thin as possible while still providing the necessary support to fin
elements 210 to allow fan assembly with a backflow stopper 200 to
be installed into electronics enclosures having limited space
constraints. It is also desirable that flex limiter elements 212
have minimal structure to avoid negatively impacting airflow though
fan assembly with a backflow stopper 200.
Various methods can be used to couple flex limiter elements 212 to
frame 204. FIG. 2 illustrates frame 204 having coupling holes 216
so that mechanical fasteners can be used to couple one or more flex
limiter elements 212 to frame 204. Suitable mechanical fasteners
comprise screws, bolts, push-in rivets, snap-lock fasteners or
other fastener compatible with coupling holes 216. Alternatively,
flex limiter elements 212 can couple to frame 204 using snap-lock
features. Adhesives, tapes and welds can also be used to couple
flex limiter elements 212 to frame 204.
Flex limiter elements 212 can be constructed from a variety of
materials. Some considerations when selecting materials for flex
limiter elements 212 include cost, stiffness and environmental
factors. Environmental factors are considered when selecting
material for flex limiter elements 212 because fan assembly with a
backflow stopper 200 can be used inside of electronics enclosures
and must meet certain industry standards. For example, flex limiter
elements 212 might have a U.L. approved fire rating of 94 V-0 or
better. Metals, alloys, polymers, ceramics, composites or other
materials having desirable properties can be used to manufacture
flex limiter elements 212.
Methods of manufacturing flex limiter elements 212 depend on the
material used for construction. For example, stamping operations or
laser cutting are appropriate manufacturing methods if metals or
alloys are used for flex limiter elements 212.
FIG. 3 illustrates electronics enclosure with backflow prevention
300 for housing sleds 320 for supporting electronic devices. FIG. 3
illustrates enclosure 318 having excess interior room for the sake
of illustration. Electronics enclosure with backflow prevention 300
includes one or more fan assemblies with backflow preventers 302.
Fan assembly with a backflow preventer 302 provides an example of
fan assembly with a backflow stopper 200; however, fan assembly
with a backflow preventer 302 can have alternative configurations
and operations than fan assembly with a backflow stopper 200. Fan
assembly with a backflow preventer 302 comprises fan 314 and
backflow preventer 316. Backflow preventer 316 is an example of
backflow stopper assembly 100 and backflow stopper assembly 202;
however, backflow preventer 316 can have alternative configurations
and operations than backflow stopper assembly 100 or backflow
stopper assembly 202.
Electronics enclosure with backflow prevention 300 comprises
enclosure 318 configured to encase and support sleds 320 containing
electronic devices and one or more fans 314 each with a
corresponding backflow preventer 316. Backflow preventers 316
comprise frame 304, fin array 306 and flex limiter elements 312.
Frame 304 is configured to structurally support fin array 306 and
couple fin array 306 to fan 314. Fin array 306 comprises a
plurality of flexural deformation elements 308 and associated fin
elements 310 arrayed in a radial arrangement to establish a pathway
for airflow, each of flexural deformation elements 308 is
configured to move an attached fin element 310 responsive to
airflow impacting attached fin element 310. Backflow preventer 316
further comprises one or more flex limiter elements 312 coupled to
frame 304 and configured to limit flexure of fin elements 310
beyond a predetermined flexure in relation to frame 304 to stop
backflow of air through fin array 306.
Enclosure 318 is configured to encase and support sleds 320
containing electronic devices. In some examples, enclosure 318 does
not include sleds 320 or support structure for sleds 320. Sleds 320
provide structural and electrical support for a plurality of
electronic devices arranges in an array. Electronic devices
comprise data storage devices, computer processing units, routers
and network elements, for example. Data storage devices comprise
hard disk drives, solid state drives, and hybrid drives. Hybrid
drives are data storage devices that couple a rotating magnetic
media to a solid state memory for enhanced performance. Sleds 320
communicatively couple to electrical connectors within enclosure
318 to communicate with external devices.
Enclosure 318 includes bulkhead 322 for mounting cooling fans 314.
Bulkhead 322 comprises structural elements for mounting cooling
equipment, power and electrical connectors. Bulkhead 322 is typical
of what would be found in an electronics enclosure, such as
enclosure 318, for example. Fans 314 can be mounted on either on
the interior or exterior of bulkhead 322. Likewise, backflow
preventer 302 can be installed on either the interior or exterior
of bulkhead 322. FIG. 3 illustrates fans 314 and backflow
preventers 302 mounted on the interior of bulkhead 322. However, in
some examples fans 314 can be mounted to the exterior of bulkhead
322 and backflow preventers 302 mounted to the interior of bulkhead
604 and vice-versa. Enclosure 318 can be manufactured from various
materials comprising metals, alloys, polymers, ceramics, composites
or other materials having desirable properties.
Electronics enclosure with backflow prevention 300 comprises one or
more fans 314. Fans 314 can mount to bulkhead 322 either on the
interior or exterior of enclosure 318. Likewise, backflow preventer
316 can be installed on either the interior or exterior of
enclosure 318. FIG. 3 illustrates fan assembly with backflow
preventer 302 mounted on the interior back-side of enclosure 318.
However, fan assembly with backflow preventer 302 can be mounted to
the front, top and bottom and interior and exterior of electronics
enclosure 318. In some examples fans 314 can be mounted to the
interior of enclosure 318 and backflow preventers 316 mounted to
the exterior of enclosure 318 and vice-versa.
Fan 314 comprises a mechanical fan with rotating blades to create
airflow. Fan 314 can comprise an axial-flow, centrifugal or
cross-flow type fan, for example. Axial-flow fans have blades that
force air to move parallel to the shaft about which the blades
rotate and are commonly used for cooling electronic equipment and
typically comprise case mount frames for mounting the fan within an
electronics enclosure. Fan 314 further comprises a motor. Some
suitable motors for use with Fan 214 include AC, DC brushed or DC
brushless motors.
Frame 304 is configured to structurally support fin array 306 and
couple fin array 306 to fan 314. Frame 304 is configurable to
structurally support fin array 306 by coupling to fin array 306.
The depth of frame 304 is determined by the depth of fin array 306.
Frame 304 permits fin elements 310 to fully open without
interfering with fan 314. Mechanical fasteners can be used to
couple frame 304 to fin array 305. Suitable mechanical fasteners
comprise screws, bolts, push-in rivets, snap-lock fasteners or
other fasteners. Alternatively, frame 304 can couple fin array 306
to fan 314 using snap-lock features. Adhesives, tapes and welds can
also be used to couple fin array 306 to frame 304. Alternatively,
in some examples, frame 304 comprises an intermediate plate,
compressed between fin array 306 and bulkhead 322 by fasteners
secured into bulkhead 322.
One or more flex limiter elements 312 couple to frame 304.
Mechanical fasteners can be used to couple flex limiter elements
312 to frame 304. Suitable mechanical fasteners comprise screws,
bolts, push-in rivets, snap-lock fasteners or other fasteners.
Alternatively, one or more flex limiter elements 312 can couple to
frame 304 using snap-lock features. Adhesives, tapes and welds can
also be used to couple one or more flex limiter elements 312 to
frame 304.
Frame 304 can be manufactured from various materials comprising
metals, alloys, polymers, ceramics, composites or some other
materials having desirable properties. The method of manufacturing
frame 304 is dependent on the material used for construction. For
example, metals or alloys can be machined or punched, while
polymers can be injection molded or vacuum formed.
Fin array 306 comprises a plurality of flexural deformation
elements 308 and associated fin elements 310 arrayed in a radial
arrangement to establish a pathway for airflow, each flexural
deformation element 308 is configured to move an attached fin
element 310 responsive to airflow impacting attached fin element
310. Fin array 306 allows airflow to pass through in only one
direction. Airflow passes through fin array 306 when fin elements
310 are in an open position and airflow is blocked when fin
elements 310 are in a closed position. One or more flex limiter
elements 312 can be used to limit flexure of fin elements 310
beyond a predetermined flexure in relation to frame 304 to stop
backflow of air through fin array 306.
Fin array 306 is configured to have a thin depth when fin elements
310 are in an open position permitting backflow preventer 316 to be
installed on the interior of enclosure 318 having limited space
constraints. Fin array 306 can be configured to open fin elements
310 to pre-determined angles in relation to a plane parallel to fin
array 306 to meet limited space constraints. For example, fin array
306 can be configured to open fin elements 310 to 40.degree.,
45.degree. or 90.degree. in relation to a plane parallel to fin
array 306. Opening fin elements 310 to 90.degree. will consume a
greater depth than opening the same fin elements 310 only
40.degree.. Similarly, the size of fin elements 310 impacts the
depth of fin array 306. Smaller and more numerous fin elements 310
consume less depth than larger and less numerous fin elements 310
while permitting the same volume of airflow. Additionally, fin
array 306 is configurable to default to either an open or closed
state depending upon the intended application. In this example, fin
array 306 defaults to an open state, thereby reducing load on fans
314 when operating.
Fin array 306 is configurable to selectively open or close
individual fin elements 310 via flexural deformation elements 308
depending upon airflow impacting the individual fin elements 310.
Flexural deformation elements 308 are configured to move an
attached fin element 310 responsive to airflow impacting fin
element 310. Flexural deformation elements 308 can be configured to
move an attached fin element 310 differing amounts responsive to
the same airflow simply by changing the geometry of flexural
deformation elements 308. For example, provided the thickness and
material of the flexural deformation elements 308 are equal, a
wider flexural deformation element 308 will be less impacted than a
narrower flexural deformation element 308 by the same airflow.
Another way to configure fin array 306 to have selectively opening
and closing fin elements 310 is to use different materials for
flexural deformation elements 308.
Fin array 306 can be formed from a single piece of a flexible
material of a predetermined thickness that establishes an open
state of fin array 306 when the airflow is provided by fan 314 and
a closed state of fin array 306 when the airflow is in a direction
opposite to that provided by fan 314. Alternatively, fin array 306
can be formed from a laminated assembly of one or more flexible
materials with a first layer of the laminated assembly of a first
thickness that establishes an open state of fin array 306 when the
airflow is provided by fan 314 and a closed state of fin array 306
when the airflow is in a direction opposite to that provided by fan
314, and the second layer of the laminated assembly of a second
thickness to form fin elements 310 and provide rigidity to fin
elements 310. Some considerations when selecting materials for
flexural deformation elements 308 include cost, stiffness, and
environmental factors. Flexural deformation elements 308 flex to
open and close fin elements 310, therefore the stiffness, or the
modulus of elasticity, affects how flexural deformation elements
308 react to changes in airflow. Stiffness of flexural deformation
elements 308 can be adjusted when using the same piece of material
for fin elements 310 and flexural deformation elements 308 by
selectively removing material to form flexural deformation elements
308. Flexural deformation elements 308 can be cut from the same
piece of material as fin elements 310. Alternatively, flexural
deformation elements 308 can comprise different materials than fin
elements 310. In this case, both material selection and geometry of
flexural deformation elements 308 will determine the stiffness of
flexural deformation elements 308.
Environmental factors are considered when selecting material for
flexural deformation elements 308 because backflow preventer 316
can be used inside of enclosure 318 and must meet certain industry
standards. For example, flexural deformation elements 308 might
have a U.L. approved fire rating of 94 V-0 or better. In some
examples, flexural deformation elements 308 can experience
temperatures ranging from 40.degree. C. to 60.degree. C. in
operation. Therefore, structural integrity of a material at
temperature and pressure might be considered to prevent flexural
deformation elements 308 from experiencing creep or otherwise
losing shape at elevated operating temperatures and pressures.
Metals, alloys, and flame retardant materials are good examples of
materials that can be used for flexural deformation elements 308.
High-density polyethylene or ITWFormex.RTM. provide two examples of
materials that can be used for flexural deformation elements 308
and meet U.L. approved fire rating of 94 V-0 or better.
Various methods of manufacturing flexural deformation elements 308
can be employed depending upon the material selected. For example,
some materials that can be used to make flexural deformation
elements 308 are easily manufactured using stamping, die cutting
and laser cutting operations. While other materials may be better
suited to injection molding, vacuum forming, scoring or some other
operations. In some examples, fin array 306 can be constructed from
flexural deformation elements 308 made of one material and fin
elements 310 from another. Dissimilar materials can be assembled to
form fin array 306 by using lamination techniques, adhesives, heat
bonds or other mechanical joining processes.
Fin elements 310 close in the event of fan 314 failures thereby
preventing backflow that would compromise the efficiency of the
cooling system. Flexural deformation elements 308 coupled to fin
elements 310 flex to open and close fin elements 310. Flexural
deformation elements 308 elements are configurable to react to
changes in airflow and open and close fin elements 310 in response.
The flexure of flexural deformation elements 308 can be configured
by material selection and geometry. Fin elements 310 bear a minimal
structural load by airflow in the open position. Fin elements 310
are structurally loaded by airflow in the closed position. Flex
limiter elements 312 provide additional support to fin elements 310
when fin elements 310 experience load in the closed position.
Therefore, material strength is not a critical factor when
selecting materials for fin elements 310.
Some considerations when selecting materials for fin elements 310
include cost, stiffness, and environmental factors. Environmental
factors are considered when selecting material for fin elements 310
because fan assembly with a backflow preventer 302 can be used
inside of enclosure 318 and must meet certain industry standards.
For example, fin elements 310 might have a U.L. approved fire
rating of 94 V-0 or better. In some examples, fin elements 310 can
experience temperatures ranging from 40.degree. C. to 60.degree. C.
in operation. Therefore, structural integrity of a material at
temperature and pressure might be considered to prevent fin
elements 310 from experiencing creep or otherwise losing shape at
elevated operating temperatures and pressures. Metals, alloys, and
flame retardant materials are good examples of materials that can
be used for fin elements 310. High-density polyethylene or
ITWFormex.RTM. provide two examples of materials that can be used
for fin elements 310 and meet U.L. approved fire rating of 94 V-0
or better.
Various methods of manufacturing fin elements 310 can be employed
depending upon the material selected. For example, some materials
that can be used to make fin elements 310 are easily manufactured
using stamping, die cutting and laser cutting operations. While
other materials may be better suited to injection molding, vacuum
forming, scoring or some other operations. In some examples, fin
array 306 can be constructed from fin elements 310 made of one
material and flexural deformation elements 308 from another.
Dissimilar materials can be assembled to make fin array 306 by
using lamination techniques, adhesives, heat bonds or other
mechanical joining processes.
One or more flex limiter elements 312 couple to frame 304 and are
configured to limit flexure of fin elements 310 beyond a
predetermined flexure in relation to frame 304 to stop backflow of
air through fin array 306. Flex limiter elements 312 limit flexure
of fin elements 310 beyond a predetermined flexure in relation to
frame 304 to stop backflow of air through fin array 306 by
providing mechanical interference with fin elements 310 thereby
inhibiting further movement. Flex limiter elements 312 allow fin
elements 310 to be constructed of lighter and more flexible
materials by providing additional support to fin elements 310
during load. It is desirable for flex limiter elements 312 to be as
thin as possible while still providing the necessary support to fin
elements 310 to allow fan assembly with a backflow preventer 302 to
be installed into electrical enclosures having limited space
constraints. It is also desirable that flex limiter elements 312
have minimal structure to avoid negatively impacting airflow though
fan assembly with a backflow preventer 302.
Various methods can be used to couple flex limiter elements 312 to
frame 304. Mechanical fasteners can be used to couple flex limiter
elements 312 to frame 304. Suitable mechanical fasteners comprise
screws, bolts, push-in rivets, snap-lock fasteners or other
fasteners. Alternatively, flex limiter elements 312 can couple to
frame 304 using snap-lock features. Adhesives, tapes and welds can
also be used to couple flex limiter elements 312 to frame 304.
Flex limiter elements 312 can be constructed from a variety of
materials. Some considerations when selecting materials for flex
limiter elements 312 include cost, stiffness, and environmental
factors. Environmental factors are considered when selecting
material for flex limiter elements 312 because backflow preventer
316 can be used inside of enclosure 318 and must meet certain
industry standards. For example, flex limiter elements 312 might
have a U.L. approved fire rating of 94 V-0 or better. Metals,
alloys, polymers, ceramics, composites or some other materials
having desirable properties can be used to manufacture flex limiter
elements 312.
Methods of manufacturing flex limiter elements 312 depend on the
material used for construction. For example, some materials that
can be used to make fin elements 312 are easily manufactured using
stamping, die cutting and laser cutting operations. While other
materials may be better suited to injection molding, vacuum
forming, or scoring operations. Alternatively, flex limiter
elements can be manufactured using polymers and injection molding
techniques.
FIGS. 4A and 4B illustrate the operation of backflow stoppers 402
within enclosure 418. Backflow stopper 402 is an example of
backflow stopper assembly 100, backflow stopper assembly 202 and
backflow preventer 316; however, backflow stopper 402 may have
alternative configurations and methods of operation than backflow
stopper assembly 100, backflow stopper assembly 202 and backflow
preventer 316.
During normal operation airflow is drawn from the front of
enclosure (illustrated as the right side of enclosure 418 in FIGS.
4A and 4B) evenly past electronic devices 420, absorbing heat from
electronic devices 420, and exhausted out the back of enclosure 418
(illustrated as the left side of enclosure 418 in FIGS. 4A and 4B).
Some examples of enclosure 418 allow airflow to be drawn in from
the top, bottom, and sides of enclosure 418. Fan 424 failure will
result in similar inefficient airflow modes when fan 424 fails in
either example. Therefore, for the sake of simplicity in
explanation, it is assumed that during normal operation airflow is
drawn evenly from the front to the back of enclosure 418 to cool
electronic devices 420.
FIG. 4A illustrates airflow within enclosure 418 when fan 424 fails
and does not have backflow stopper 402 installed. When fan 424
fails without a backflow stopper 402, failing fan 424 becomes the
path of least resistance for airflow. In this example fan 414 is
still operational after fan 424 fails. Fan 414 draws some airflow
past electronic devices 420; however, failing fan 424 provides a
pathway for airflow with lesser resistance than airflow drawn from
the front of enclosure 418 and past electronic devices 420 thereby
circumventing cooling airflow past electronic devices 420.
FIG. 4B illustrates airflow within enclosure 418 when fan 424 fails
and backflow stoppers 402 are installed. Enclosure 418 comprises
backflow stoppers 402, fan 416, electronic devices 420, and failing
fan 424. Backflow stopper 402 closes fin elements thereby blocking
backflow through fan 424 when fan 424 fails. Fan 424 is no longer
the pathway for least resistance as in FIG. 4A. Fan 414 continues
to draw air from the front of enclosure 418, past electronic
devices 420 and exhausts the air out of the back of enclosure
418.
FIG. 5 illustrates an assembled view and an exploded view of
backflow preventer assembly 500. Backflow preventer assembly 500 is
an example of backflow stopper assembly 100, backflow stopper
assembly 202, backflow preventer 316 and backflow stopper 402;
however, backflow preventer assembly 500 may have alternative
configurations and methods of operation than backflow stopper
assembly 100, backflow stopper assembly 202, backflow preventer 316
and backflow stopper 402.
Backflow preventer assembly 500 comprises frame 504, fin array 506
and fin array retainer 524. Frame 504 is configured to structurally
support fin array 506 and couple fin array 506 to a fan. Fin array
506 comprises a plurality of flexural deformation elements 508 and
associated fin elements 510 arrayed in a radial arrangement to
establish a pathway for airflow, each of flexural deformation
elements 508 is configured to move an attached fin element 510
responsive to airflow impacting attached fin element 510. One or
more flex limiter elements 512 integral to frame 504 are configured
to limit flexure of fin elements 510 beyond a predetermined flexure
in relation to frame 504 to stop backflow of air through fin array
506.
Backflow preventer assembly 500 comprises frame 504, fin array 506
and fin array retainer 524 coupled together by snap-locking
elements 526 to create a complete backflow preventer assembly 500.
Frame 504 comprises large reference stud 540 and small reference
stud 542 to position fin array 506 and fin array retainer 524 in
relation to frame 504 and each other. Fin array 506 comprises pairs
of fin elements 510 that open and close fin elements 510 in
opposing pairs responsive to airflow allowing fin array 506 to have
less depth than using a single fin element 510 to cover the same
surface area. In this example, backflow preventer assembly 500 has
a depth of less than 20 millimeters. Fin limiter elements 512 are
integral to frame 504 in this example.
Frame 504 is configured to structurally support fin array 506 and
couple fin array 506 to a fan. Frame 504 comprises large reference
stud 540 and small reference stud 542 configured to engage large
reference hole 534 and small reference hole 538 of fin array 506 to
position fin array 506 in relation to frame 504. Large reference
stud 540 and small reference stud 542 also engage large reference
hole 528 and small reference hole 530 of fin array retainer 524 to
position fin array retainer 524 in relation to frame 504 an fin
array 506. Frame 504 includes interior spoke-like structural
members radiating outward from a central hub to structurally
support fin array 506 between flexural deformation elements 508 and
fin elements 510. Fin array retainer 524 structurally supports fin
array 506 by applying pressure to fin array 506 against the
spoke-like structural members of frame 504 by engaging snap-locking
elements 526 of fin array retainer 524 with coupling hole 536 of
fin array 506 and snap-lock coupling hole 544 of frame 504. Frame
504 includes fan coupling holes 546 for coupling fin array 506 to a
fan. Frame 504 is comprised of an injection moldable polymer. Frame
504 is manufactured using injection molding methods.
Fin array 506 comprises a plurality of flexural deformation
elements 508 and associated fin elements 510 arrayed in a radial
arrangement to establish a pathway for airflow, each of flexural
deformation elements 508 is configured to move an attached fin
element 510 responsive to airflow impacting attached fin element
510. Fin array 506 allows airflow to pass through in only one
direction. Airflow passes through fin array 506 when fin elements
510 are in an open position and airflow is blocked when fin
elements 510 are in a closed position. FIG. 5 illustrates fin array
506 with fin elements 510 fully open. While not illustrated in FIG.
5, fin array 506 further comprises one or more flexural deformation
elements 508 each individually configurable to flex and move an
attached fin element 510 a pre-determined amount in relation to
other flexural limiting elements 508 and fin elements responsive
510 to airflow. This allows backflow preventer assembly 500 to
mitigate detrimental impact caused to airflow within an electronics
enclosure in the event that the fan is failing, but has not
completely failed. Backflow preventer assembly 500 can close a
portion of fin elements 510 responsive to airflow. For example, if
the fan is only operating at one-half capacity, flexural limiting
elements 508 can close one-half of fin elements 510. Fin array 506
defaults to an open state in this example.
Flexural deformation elements 508 couple to fin elements 510 and
open and close fin elements 510 by flexing. Flexural deformation
elements 508 can be configured to respond differently to particular
airflows. For example, flexural deformation elements 508 having a
high degree of stiffness, or a high modulus of elasticity, will not
flex as much as flexural deformation elements 508 having a lower
degree of stiffness, or modulus of elasticity, given the same
airflow. Thus, flexural deformation elements 508 can be configured
to flex in response to varying airflows.
Flexural deformation elements 508 can be made in several ways.
Flexural deformation elements 508 can be configured to move an
attached fin element 510 differing amounts responsive to the same
airflow simply by changing the geometry of flexural deformation
elements 508. Another way to configure fin array 506 to have
selectively opening and closing fin elements 510 is to use
different materials for flexural deformation elements 508. Flexural
deformation elements 508 can comprise a long beam. In the case of a
long beam, flexural deformation elements 508 can utilize bending or
torsional properties of the beam. Flexural deformation elements 508
can be made from a thin section by selecting a thin sheet or by
scoring (removing thickness locally). FIG. 5 provides an example of
flexural deformation elements 508 by selecting a thin sheet.
Additionally, flexural deformation elements can be made by
narrowing a section of material to achieve desirable flexural
deformation properties. For example, provided the thickness and
material of the flexural deformation elements 508 are generally
equal, a wider flexural deformation element 508 will be less
impacted than a narrower flexural deformation element 508 by the
same airflow. Finally, a combination of all the above methods can
be used to make flexural deformation elements 508.
In this example, fin array 506 comprises flexural deformation
elements 508 and fin elements 510 comprised of a laminated assembly
of one or more flexible materials with a first layer of the
laminated assembly of a first thickness that establishes an open
state of fin array 506 when the airflow is provided by the fan and
a closed state of fin array 506 when the airflow is in a direction
opposite to that provided by the fan, and the second layer of the
laminated assembly of a second thickness to form fin elements 510
and provide rigidity to fin elements 510.
Fin array 506 includes large reference hole 534 and small reference
hole 538 for positioning fin array 506 in relation to frame 504.
Snap-locking elements 526 of fin array retainer 524 engage fan
coupling hole 546 of fin array 506 and snap-lock coupling hole 544
of frame 504 to hold backflow preventer assembly 500 together.
Some considerations when selecting materials for flexural
deformation elements 508 include cost, stiffness, and environmental
factors. Flexural deformation elements 508 flex to open and close
fin elements 510, therefore the stiffness, or the modulus of
elasticity, affects how flexural deformation elements 508 react to
changes in airflow. Stiffness of flexural deformation elements 508
can be configured to flex in response to differing airflows by
selecting, material, thickness and by selectively removing material
to form flexural deformation elements 508.
Environmental factors are considered when selecting material for
flexural deformation elements 508 because backflow preventer
assembly 500 can be used inside of an electronics enclosure and
must meet certain industry standards. For example, flexural
deformation elements 508 might have a U.L. approved fire rating of
94 V-0 or better. In some examples, flexural deformation elements
508 can experience temperatures ranging from 40.degree. C. to
60.degree. C. in operation. Therefore, structural integrity of a
material at temperature and pressure might be considered to prevent
flexural deformation elements 508 from experiencing creep or
otherwise losing shape at elevated operating temperatures and
pressures. Metals, alloys, and flame retardant materials are good
examples of materials that can be used for flexural deformation
elements 508. High-density polyethylene or ITWFormex.RTM. provide
two examples of materials that can be used for flexural deformation
elements 508 and meet U.L. approved fire rating of 94 V-0 or
better.
Fin elements 510 close in the event of cooling fan failure thereby
preventing backflow that would compromise the efficiency of the
cooling system. Flexural deformation elements 508 coupled to fin
elements 510 flex to open and close fin elements 510. Flexural
deformation elements 508 elements are configurable to react to
changes in airflow and open and close fin elements 510 in response.
The flexure of flexural deformation elements 508 can be configured
by material selection and geometry. Fin elements 510 bear a minimal
structural load by airflow in the open position. Fin elements 510
are structurally loaded by airflow in the closed position. Flex
limiter elements 512 provide additional support to fin elements 510
when fin elements 510 experience load in the closed position.
Therefore, material strength is not a critical factor when
selecting materials for fin elements 510.
Some considerations when selecting materials for fin elements 510
include cost, stiffness, and environmental factors. Environmental
factors are important to consider when selecting material for fin
elements 510 because backflow preventer assembly 500 can be used
inside of electronics enclosures and must meet certain industry
standards. For example, fin elements 510 might have a U.L. approved
fire rating of 94 V-0 or better. In some examples, fin elements 510
can experience temperatures ranging from 40.degree. C. to
60.degree. C. in operation. Therefore, structural integrity of a
material at temperature and pressure might be considered to prevent
fin elements 510 from experiencing creep or otherwise losing shape
at elevated operating temperatures and pressures. Metals, alloys,
and flame retardant materials are good examples of materials that
can be used for fin elements 510. High-density polyethylene or
ITWFormex.RTM. provide two examples of materials that can be used
for fin elements 510 and meet U.L. approved fire rating of 94 V-0
or better.
Various methods of manufacturing fin elements 510 can be employed
depending upon the material selected. For example, some materials
that can be used to make fin elements 510 are easily manufactured
using stamping, die cutting and laser cutting operations. While
other materials may be better suited to injection molding, vacuum
forming, scoring or some other operations.
FIG. 5 illustrates backflow preventer assembly 500 having multiple
flex limiter elements 512 integral to frame 504 configured to limit
flexure of fin elements 510 beyond a predetermined flexure in
relation to frame 504 to stop backflow of air through fin array
506. Flex limiter elements 512 limit flexure of fin elements 510
beyond a predetermined flexure in relation to frame 504 to stop
backflow of air through fin array 506 by providing mechanical
interference with fin elements 510 thereby inhibiting further
movement. Flex limiter elements 512 allow fin elements 510 to be
constructed of lighter and more flexible materials by providing
additional support to fin elements 510 during load. It is desirable
that flex limiter elements 512 have minimal structure to avoid
negatively impacting airflow though backflow preventer assembly
500.
Fin array retainer 524 comprises snap-locking elements 526, large
reference hole 528, small reference hole 530, and retainer spokes
532. Snap-locking elements 526 engage coupling hole 536 of fin
array 506 and snap-lock coupling hole 544 of frame 504 to hold
backflow preventer assembly 500 together. Large reference hole 528
and small reference hole 530 position fin array retainer 524 in
relation to frame 504 and fin array 506. Retainer spokes 532
provide structural support for fin array 506 by securing fin array
506 to frame 504. Fin array retainer is manufactured from injection
moldable polymer by an injection molding process.
FIGS. 6A and 6B illustrate the operation of backflow preventer
assembly 500. FIG. 6A illustrates backflow preventer assembly 500
in a closed state to prevent backflow of air through fin elements
510. Fin elements 510 are in contact with flex limiter elements 512
in the closed position providing fin elements 510 with additional
structural support. FIG. 6B illustrates backflow preventer assembly
500 in an open state allowing airflow through fin elements 510.
FIG. 6A illustrates an example of backflow preventer assembly 500
in a closed state to prevent backflow of air through a fan. While
the fan is not illustrated in FIG. 6A it is assumed for the sake of
explanation that the fan has failed and flexural deformation
elements 508 have closed fin elements 510 to prevent backflow of
air through the fan. A plurality of flex limiter elements 510
integral to frame 504 provide additional structural support to fin
elements 510 when fin elements 510 experience load. FIG. 6A
illustrates fin elements 510 blocking airflow.
FIG. 6B illustrate an example of backflow preventer assembly 500 in
an open state allowing airflow through a fan. While the fan is not
illustrated in FIG. 6B it is assumed for the sake of illustration
that the fan is operational and flexural deformation elements 508
are in a default open state. FIG. 6B illustrates airflow through
the pathway for airflow of fin array 506.
FIG. 7 illustrates a bulkhead assembly with fans and backflow
preventers 700 similar to what is typically found in electronic
enclosures such as enclosure 318 or enclosure 418, for example.
Backflow preventer 702 is an example of backflow stopper assembly
100, backflow stopper assembly 202, backflow preventer 316,
backflow stopper 402 and backflow preventer assembly 500; however,
backflow preventer 702 may have alternative configurations and
methods of operation than backflow stopper assembly 100, backflow
stopper assembly 202, backflow preventer 316, backflow stopper 402
and backflow preventer assembly 500.
Bulkhead assembly with fans and backflow preventers 700 comprises a
plurality of backflow preventers 702, bulkhead 704, screws 706, a
plurality of electrical connectors 708, and a plurality of fans
714. Backflow preventers 702 are coupled to fans 714. Fans 714
mount to bulkhead 704 using screws 706. Electrical connectors 708
communicatively couple to electronic devices, such as data storage
devices held inside an electronics enclosure.
Backflow preventers 702 block airflow through fans 714 in the event
one or more fans 714 fails, thereby blocking the path of least
resistance for airflow and forcing airflow to continue passing over
electronic components within the electronics enclosure. FIG. 7
illustrates fans 714 in working order and backflow preventers 702
in an open state allowing airflow to pass through backflow
preventers 702.
Bulkhead 704 comprises structural elements for mounting cooling
equipment, power and electrical connectors. Bulkhead 704 is typical
of what would be found in an electronics enclosure, such as
enclosure 318, for example. Fans 714 can be mounted on either on
the interior or exterior of bulkhead 704. Likewise, backflow
preventer 702 can be installed on either the interior or exterior
of bulkhead 704. FIG. 7 illustrates fans 714 and backflow
preventers 702 mounted on the interior of bulkhead 704. However, in
some examples fans 714 can be mounted to the exterior of bulkhead
704 and backflow preventers 702 mounted to the interior of bulkhead
704 and vice-versa.
Backflow preventers 702 comprise a frame configured to structurally
support a fin array when coupled to fans 714. The fin array
comprising a plurality of flexural deformation elements and
associated fin elements arrayed in a radial arrangement to
establish a pathway for airflow, each of the flexural deformation
elements configured to move an attached fin element responsive to
airflow impacting the attached fin element; and one or more flex
limiter elements coupled to the frame and configured to limit
flexure of the fin elements beyond a predetermined flexure in
relation to the frame to stop backflow of air through the fin
array.
Backflow preventers 702 block airflow through fans 714 when the fin
array is in a closed state. Flexural deformation elements couple to
fin elements and open and close fin elements by flexing. The
flexibility of flexural deformation elements determines how fin
array will react to differing airflows. Flexural deformation
elements having a high degree of stiffness, or modulus of
elasticity, will flex less than flexural deformation elements
having a lesser degree of stiffness, or modulus of elasticity,
given the same airflow.
The fin array can be formed from a single piece of a flexible
material of a predetermined thickness that establishes an open
state of the fin array when the airflow is provided by the fan and
a closed state of the fin array when the airflow is in a direction
opposite to that provided by the fan. Alternatively, the fin array
can be a laminated assembly of one or more flexible materials with
a first layer of the laminated assembly of a first thickness that
establishes an open state of the fin array when the airflow is
provided by the fan and a closed state of the fin array when the
airflow is in a direction opposite to that provided by the fan, and
the second layer of the laminated assembly of a second thickness to
form the fins and provide rigidity to the fins.
While not illustrated in FIG. 7, the one or more flex limiter
elements are integral to the frame in this example. The plurality
of flex limiter elements are configured to limit flexure of the fin
elements beyond a predetermined flexure in relation to the frame to
stop backflow of air through the fin array. The flex limiter
elements also provide structural support to the fin elements when
the fin array is under load in a closed state.
Fans 714 comprise axial-flow fans with case mount frames for
mounting to bulkhead assembly with fans and backflow preventers
700. Fans 714 further comprise motors. Some suitable motors for use
with fans 714 include AC, DC brushed or DC brushless motors.
Drives which incorporate rotating media, such as rotating magnetic
media of hard disk drives or hybrid disk drives, among others, also
include various electromechanical elements to position read/write
heads over the spinning media. These electromechanical elements
include armatures, motors, actuators, voice coils, servos, or other
elements which can be affected by vibration of the drive elements
themselves or by vibrational environment in which the drives are
included. This vibrational environment can include vibrations or
acoustic disturbances introduced by the ventilation fans, as well
as the drives themselves. For example, a drive which performs many
random read/write operations can induce more vibration into the
surrounding environment of that drive due to rapid movements of the
associated electromechanical elements within the drive. Other
components within a storage enclosure, such as fans, can also
affect the vibration levels within an associated enclosure.
FIG. 8 illustrates a backflow assembly 800 configured to reduce
vibrations or acoustic disturbances on the drives that are
introduced by the ventilation fans. Backflow assembly 800 includes
a backflow preventer 801 that is an example of backflow stopper
assembly 100, backflow stopper assembly 202, backflow preventer
316, backflow stopper 402, backflow preventer assembly 500, and
backflow preventer 702. However, backflow preventer 801 may have
alternative configurations and methods of operation than the
backflow preventers and assemblies presented above.
To reduce vibrations or acoustic disturbances within an enclosure,
an acoustic barrier assembly 804 having first and second acoustic
barrier plates 806, 808. Thus, backflow assembly 800 forms a
backflow stopper with integrated acoustic barrier assembly. First
and second acoustic barrier plates 806, 808 include respective
pluralities of airflow passages 810, 812 formed therethrough. While
backflow assembly 800 is shown with first and second acoustic
barrier plates 806, 808, additional acoustic barrier plate layers
may be incorporated therein. Additionally, while first and second
acoustic barrier plates 806, 808 are shown as plates independently
added to the front and back sides of backflow preventer 801,
acoustic dampening layers 806, 808 may instead be added onto the
flaps, inside, front, and back of the backflow preventer 801.
FIG. 9 illustrates a schematic diagram of a data storage system 900
incorporating backflow assembly 800. Data storage system 900
includes an electronics chassis or enclosure 902 housing a data
storage array 904 of one or more data storage devices 906. A fan
assembly 908 having one or more fans 910 or other cooling and
ventilation elements for providing airflow 912 to the elements of
data storage system 900. Airflow 912 is drawn through openings 914
on a first side of enclosure 902 and expelled through openings 916
on a second side of enclosure 902.
To reduce negative effects to the rate of airflow 912 through the
electronics enclosure 902 and the cooling performance of the fan
assembly 908, acoustic barrier assembly 804 is constructed such
that its impedance to airflow 912 is lower than the impedance of
the other components within the electronics enclosure 902 to
airflow 912 without the acoustic barrier assembly 804 in the system
900. In this manner, the flow of airflow 912 through the system 900
is not significantly affected through the addition of the acoustic
barrier assembly 804.
Attenuation via the acoustic barrier assembly 804 occurs as
acoustic waves get absorbed by or reflect off of the surfaces of
the first and second acoustic barrier plates 806, 808 prior to
reaching the data storage array 904 and other electronic devices
within the electronics enclosure 902. Maximizing effectiveness of
acoustic attenuation by the acoustic barrier assembly 804 includes
offsetting passages 810, 812 formed in a non-overlapping or offset
arrangement such that a direct line-of-sight is blocked between the
fans 910 of the fan assembly 908 and the electronic storage devices
906 within the electronics enclosure 902. In this manner, acoustic
waves emanating from the fan assembly 908 do not impinge on the
data storage array 904 without being at least reflected or
redirected multiple times through the acoustic barrier assembly
804. The acoustic waves may be reflected or redirected entirely
away from the interior of the enclosure 902 (as illustrated by
acoustic waves 918, 920) and may be reflected multiple times
through the acoustic barrier assembly 804 (as illustrated by
acoustic waves 922, 924) before penetrating into the interior of
enclosure 902, which decreases their intensity.
In addition, at least a portion of the energy of acoustic waves
emanating from the fan assembly 908 may be absorbed by the material
of the first and second acoustic barrier plates 806, 808 such that
they are blocked from penetrating into the interior of enclosure
902. A portion of the energy of the acoustic waves may also be
absorbed by the material of the plurality of flexural deformation
elements 801 or the fin elements 802 of backflow preventer 801. For
example, FIG. 9 illustrates an acoustic wave 926 reflecting
multiple times through the acoustic barrier assembly 804 and
getting absorbed by first acoustic barrier plate 806. The more
times an acoustic wave is forced to come into contact with the
first and second acoustic barrier plates 806, 808 through
reflection, the greater the ability the acoustic barrier assembly
804 has of significantly reducing or entirely absorbing its
intensity. The material of first and second acoustic barrier plates
806, 808 can comprise foams, polymers, metal foams, glass fibers,
cellulose, baffles, resonant chambers, or other materials and
elements that absorb or trap acoustic waves at disturbance
frequencies.
FIG. 10 shows three assembled backflow assemblies 1000, 1002, 1004
modeled after backflow assembly 800 and mounted into bulkhead 704
of FIG. 7. As can be seen, the design of assemblies 1000-1004 is
space-saving and uses the space already existing in the bulkhead
704. Thus, cross-flow of the airflow within the enclosure is not
obstructed.
FIG. 11 illustrates an assembled view of a backflow assembly 1100
configured to reduce vibrations or acoustic disturbances on the
drives that are introduced by the ventilation fans. Backflow
assembly 1100 blocks airflow from passing through a fan in the
event the fan fails. In addition, backflow assembly 1100 is
configured to reduce vibrations or acoustic disturbances within an
enclosure caused by the ventilation fans. Backflow assembly 1100 is
an example of backflow stopper assembly 100, backflow stopper
assembly 202, backflow preventer 316, backflow stopper 402,
backflow preventer assembly 500, backflow preventer 702, and
backflow preventer 801. However, backflow preventer 1100 may have
alternative configurations and methods of operation than the
backflow preventers and assemblies presented above.
Backflow assembly 1100 includes a frame 1102, fin array 1104, and
flex limiter elements 1106. Fin array 1104 comprises a plurality of
fins 1108-1114 arrayed in an arrangement about frame 1102 to
establish a pathway for airflow, each fin 1108-1114 responsive to
airflow impacting thereon. Fins 1108, 1112 are configured to pivot
about an axis parallel to a first axis 1116 passing through frame
1102, and fins 1110, 1114 are configured to pivot about an axis
parallel to a second axis 1118 passing through frame 1102. Flex
limiter element 1106 coupled to frame 1102 is configured to limit
flexure or pivoting of fins 1108-1114 beyond the boundaries of
frame 1102 to stop backflow of air therethrough. Fin array 1104
allows airflow to pass through in only one direction. Airflow
passes through fin array 1104 when fins 1108-1114 are in an open
position and airflow is blocked when fins 1108-1114 are in a closed
position.
Fins 1108-1114 can be formed from a single layer or from a
laminated assembly of one or more layers. Fins 1108-1114 comprises
one or more acoustically active materials that can alter acoustic
properties associated with fan assemblies to reduce negative
acoustic effects on the storage devices within an electronics
enclosure. Fins 1108-1114 accomplish acoustic effect reduction at
least through a dampening or absorption of acoustic frequencies as
well as through a redirection or reflection of the acoustic
frequencies or waves.
The material or material composition of fins 1108-1114 is designed
to dampen or absorb at least a portion of acoustic wave energy
within the material of the attenuator. Fins 1108-1114 can comprise
foams, polymers, metal foams, glass fibers, cellulose, baffles,
resonant chambers, or other materials and elements that absorb or
trap acoustic waves at disturbance frequencies.
The material of fins 1108-1114 typically has one or more
attenuation frequencies or frequency ranges over which acoustic
waves are attenuated or reduced. In a further example, fins
1108-1114 can include metamaterials that can be selectively tuned
though microstructures to dampen certain selected acoustic
frequencies.
In addition to dampening acoustic waves within the material itself,
the outer surface 1120 of the fins 1108-1114 may include contours
or other texturing 1122 designed to reflect and scatter the
acoustic waves in directions away from storage devices within the
electronics enclosure. In this manner, the waves may be reflected
before they can reach the storage devices; thus, reducing their
intensity within the electronics enclosure. In a preferable
embodiment, the texturing 1122 of the outer surface 1120 maximizes
acoustic wave scattering to minimize the amount of acoustic waves
that have a direct line of propagation toward the storage
devices.
As illustrated in FIG. 11, texture 1122 of surface 1120 includes
surface undulations designed to reflect acoustic waves away from
surface 1120 in many different directions. In one example, fins
1108-1114 are made of corrugated cardboard. The corrugated
cardboard may provide surface undulations on both sides of the fin
1108-1114. That is, while a first side of fins 1108-1114 is shown
in FIG. 11, the second, reverse side of fins 1108-1114 may present
the other side of the undulations toward the source of the acoustic
disturbance. In this manner, both undulating sides of dual-sided
fins 1108-1114 may be used to help scatter acoustic waves impinging
thereon. The surface texturing can also help with impedance
matching of the interface to the airborne acoustic waves.
FIG. 12 shows three assembled backflow assemblies 1200, 1202, 1204
modeled after backflow assembly 1100 and mounted into bulkhead 704
of FIG. 7. As can be seen, the design of assemblies 1200-1204 is
space-saving and uses the space already existing in the bulkhead
704. Thus, cross-flow of the airflow within the enclosure is not
obstructed.
The included descriptions and figures depict specific embodiments
to teach those skilled in the art how to make and use the best
mode. For the purpose of teaching inventive principles, some
conventional aspects have been simplified or omitted. Those skilled
in the art will appreciate variations from these embodiments that
fall within the scope of the invention. Those skilled in the art
will also appreciate that the features described above can be
combined in various ways to form multiple embodiments. As a result,
the invention is not limited to the specific embodiments described
above, but only by the claims and their equivalents.
* * * * *
References